Follow the author of this article

Follow the topics within this article

Coffee drinkers must clean reusable travel cups after every use to avoid potentially harmful bacteria building up inside them, Public Health England has said.

The warning appears to be directed at a rising number of office workers who are thought to be using the cups continuously throughout the day without washing them.

Reusable coffee cups' popularity has exploded in recent weeks, amid Government plans for a 25p "latte" tax on disposable cups.

A number of major coffee chains have also now started offering special discounts on drinks to incentivise the use of reusable cups, causing sales of the drinking vessels to rocket at major retailers.

Nick Phin, deputy director for national infection service, at PHE, said: “As with regular cups and glasses, wash and clean reusable cups thoroughly after every use.”

Reusable cups come in a range of different designs and are encouraged by most large coffee chains Credit:
Telegraph

Bacteria can grow when food or liquid builds up in the cup or around the mouthpiece, which can be particularly difficult to clean thoroughly on non-spill versions of the cups, experts said.

To avoid this Mr Phin recommended putting water in the cup with the lid on and shaking it. He added that as long as people applied "practical common sense" to washing their coffee cups they ought to pose no danger.

A spokesman at the Food Standards Agency also said consumers drinking from reusable cups should "ensure they are cleaned properly after every use and replaced as necessary".

He added that coffee shops could reserve the right to refuse to serve customers asking for a drink to be poured into a dirty re-usable cup.

Paul Morris, director at packaging hygiene firm AddMaster, said: "Consumers need to be aware that if a product is used more than once, there is a potential health risk if the drinking vessel has not been cleaned properly.

"This is particularly important with coffee products, where diary and sugar are present, as this is an ideal breading ground for potential dangerous bacteria.

Pret is now offering a 50p discount to customers who have a reusable cup Credit:
AFP/ JUSTIN TALLIS

"If the cup is dirty hot water alone is not good enough - you need detergent too - and if it’s OK for your hands its too cool to kill bacteria. The main danger will be from the mouthpiece which will have hard to reach areas that bacteria could grow in, so yes some would be better than others."

In recent weeks scores of MPs including Environment Secretary Micheal Gove have been seen out and about carrying reusable coffee cups.

Yesterday Mr Gove handed every member of the Cabinet a reusable coffee cup in a show of support for Theresa May's war on plastic packaging waste.

Argos, which is part of the Sainsbury’s Group, said it had sold 537 per cent more portable cups in December 2017 than the same month the previous year, while Lakeland said sales had risen by 100 per cent month-on-month.

At present the UK gets through 2.5 billion disposable coffee cups a year, virtually all of which are incinerated, exported or sent to landfill because their plastic lining makes them costly to recycle.

Earlier this month Pret a Manger doubled the discount it offers customers who use a re-usable cup to 50p on all hot drinks. Starbucks also offers a 50p discount if customers do not accept a disposable cup.